This invention relates to ethylene-carbon monoxide copolymers and more particularly to heat stable ethylene-carbon monoxide copolymer compositions.
Ethylene-carbon monoxide copolymers are of considerable interest because of their potential as engineering plastics. These materials have physical properties which are superior to many other materials commonly used in industry and, in addition, offer the advantage of low cost since carbon monoxide is readily available as a by-product in the manufacture of steel and can also be inexpensively prepared from other chemical processes.
In spite of the advantages offered by ethylenecarbon monoxide copolymers they have not attained commercial acceptance partly due to the fact that they have poor resistance to thermal degradation during post polymerization processing operations. Since polymeric end products such as films, sheets and shaped articles are mostly commonly made by heating and melting polymeric compositions and extruding or injection molding the melt it is very important that these compositions be able to withstand the temperatures encountered in such post forming operations. U.S. Pat. No. 3,156,744 discloses the use of dibasic lead phosphite as a stabilizer for ethylene-carbon monoxide copolymers.